A sloshed Bronx assistant principal with a history of DWI was busted for driving drunk to work with her 10-month-old son in the back seat thanks to a good Samaritan who amazingly got her to pull her over without incident, authorities said.

Melonie Lendor, 41, who works at IS 217 in Morrisania, refused a Breathalyzer test when cops caught up with her on the side of the New York State Thruway in Rockland County around 6:40 a.m.

She was slapped with felony DWI her third drunk driving bust.

Lendor, who lives in upstate Walden, was first spotted driving erratically by a fellow motorist, who told a 911 dispatcher that she was swerving out of her lane. He tailed her southbound towards the Tappan Zee Bridge, sources said.

Somehow he managed to get her to pull her 2004 Acura over at the Palisades Parkway exit near Clarkstown, sources said, and keep her there until cops arrived.

“She indicated she was on her way to the Bronx,” said New York State Police Sgt. John Antonelli.

Cops said she failed a field sobriety test.

Lendor’s son, who was strapped into a child safety seat in the back of the car, was unharmed and taken by a relative.

The news shocked students at her school on Fox Street, where Lendor has been an administrator since 2005.

“No wonder we didn’t see her today, said a 7th grader, who wouldn’t give her name.

“I considered her to be a role model. I didn’t expect this from her.”

Her classmate, Kiona Dalton, 12, called Lendor “a very nice person” who made us “want to stay in school.”

“She doesn’t look like the type that would do something like that. She seems very responsible.”

Lendor — who joined the city school system in 1993 as an elementary school teacher —was hit with the felony charge because of a DWI conviction within the past 10 years, police said.

She also has a conviction for driving while impaired, cops said.

Lendor was also slapped with endangering the welfare of a child, and was being held in lieu of $7,500 bail.